What Is Thyroid Function?

Video Transcript

"Hi! I'm Dr David Cathcart. I'm a family practice physician at Heartland Regional Medical Center in St. Joseph, Missouri, and I've been asked to talk to you today about thyroid disease. Thyroid function, of course is a balance between various hormonal levels. As it turns out and we hadn't really talked about this much, the thyroid is regulated in the hypothalamus which puts out a type of hormone called TSH, which puts out a hormone called thyroid stimulating hormone. Thyroid stimulating hormone when it's released by the hypothalamus that you'll see, thyroid start producing its own thyroid hormone which is T3 and T4, and then once the T levels of T3 and T4 come up, the hypothalamus measures that and recognize that the thyroid level is up so it turns off the spicket of TSH, so once the TSH starts to drop the thyroid quits producing so much T3 and T4 and so they self regulate that way. We refer to that as thyroid function and when we're testing someone for a thyroid disease either a high functioning thyroid or low functioning thyroid, we monitor their thyroid function test which include T3, T4, another test called T3 uptake and then last is the TSH, thyroid stimulating hormone. This is Dr. Cathcart and thanks for letting me talk to you about thyroid disorders."